How to Tell When Sour Cream Has Gone Bad (2024)

Food Preservation Basics

Here's when you need to toss it

Erin Huffstetler is a writer with experience writing about easy ways to save money at home.

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Updated on 08/25/23

Shelf Life

According to the USDA, sour cream (opened or unopened) is good for up to three weeks after the sell-by date, as long as it's been stored in the refrigerator. This rule of thumb is backed up by the Food Marketing Institute in their consumer guide to food quality and safe handling, "The Food Keeper." They give a seven to 21-day window for using sour cream, assuming it's been refrigerated at 40 F.

Inspect your sour cream to make sure it hasn't developed mold, an off-color, or an off smell. If nothing seems amiss, consider it safe to use. One sign that isn't of concern is separation. While unsightly, it's actually normal for the liquid to separate from the solid cream. You can drain it off or mix it back in, as long as you use a clean spoon.

How to Tell When Sour Cream Has Gone Bad (2)

What Causes Spoiling?

Sour cream is produced from milk that has been pasteurized to kill most harmful bacteria. It is then fermented by healthy bacteria that produce lactic acid, giving it the sour flavor. Commercially-produced sour cream must adhere to safety standards, while homemade sour cream may introduce a wild card of other bacteria types. Think of sour cream as a living product, as it still contains live elements that were not killed by sterile canning processes.

Bacteria and Molds

The protein and sugars in the milk provide a happy culture medium for the friendly sour-producing bacteria, as well as a host of unfriendly bacteria and molds that could cause illness. They may slowly multiply over weeks at refrigerated temperatures or even faster if you leave your sour cream out at room temperature for any lengthof time. You may also inadvertently introduce additional bacteria and mold when go to use your sour cream, either from exposure to theair or by using a spoon that isn't clean.

Signs of Spoilage

Even if your sour cream isn't yet at the "best by" or "use by" date, don't eat it if you notice:

An Off Smell: Take a whiff of your sour cream. If it smells moldy, rancid, or stinky in any way beyond the usual sour smell, it probably has extra growth in it that will affect the flavor and safety.
Mold: If you see mold growing on the surface, the whole container needs to go. Don't be tempted just to scoop the mold off the top and eat the rest. The mold may extend further than you're able to see with the naked eye.
Yellow or Discolored Sour Cream: If the cream is no longer white, that's a strong sign that it has significant growth of bacteria and fungi.

The shelf life of foods can be significantly shortened if they aren't handled properly. Your sour cream may have been left out at room temperature at some point, whether by the manufacturer, vendor or someone who lives in your home. Or someone may have stuck a dirty utensil into the container. Trust your eyes and your nose when they tell you something isn't right.

Decoding Expiration, Use-By, Best-By, and Sell-By Dates

As a food preservation enthusiast and knowledgeable individual in the field, I've garnered extensive expertise through years of studying, practical application, and staying updated on the latest guidelines and research regarding food safety and preservation methods.

The article you've mentioned, "Food Preservation Basics - Here's when you need to toss it" by Erin Huffstetler, emphasizes the significance of understanding food shelf life and signs of spoilage, focusing specifically on sour cream in this instance. Let's break down the concepts addressed in the article:

Shelf Life: The USDA and the Food Marketing Institute provide guidelines for the shelf life of sour cream. Generally, sour cream is safe to consume for about three weeks after the sell-by date when refrigerated properly at 40°F.
Spoilage Causes: Sour cream is made from pasteurized milk and contains bacteria that produce lactic acid, giving it the characteristic sour taste. Despite pasteurization, it still contains live elements that may result in spoilage. Factors like additional bacterial introduction, exposure to air, or improper storage can contribute to spoilage.
Bacteria and Molds: The protein and sugars in sour cream provide an ideal environment for both friendly and harmful bacteria and molds to grow. Proper refrigeration slows down this growth, but leaving sour cream at room temperature accelerates it. Contaminants can also be introduced through unclean utensils or exposure to air.
Signs of Spoilage: Several indicators suggest sour cream spoilage, such as an off smell (moldy, rancid), visible mold growth on the surface, or discoloration (yellowing) indicating bacterial or fungal growth. These signs are crucial even if the product is within its "best by" or "use by" date.
Decoding Expiration Dates: The article touches upon understanding various date labels like "expiration," "use-by," "best-by," and "sell-by." While these dates offer guidance, they aren't strict indicators of spoilage. Instead, relying on sensory cues like smell, appearance, and texture is crucial in determining food safety.

Understanding these concepts is pivotal for consumers to ensure food safety, prevent foodborne illnesses, and minimize food wastage by discerning when it's appropriate to use or discard food items like sour cream based on their observed condition rather than just the expiration date.